North American Network Operators Group

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RE: DS3 Coax..

  • From: Timothy R. McKee
  • Date: Sat Apr 19 21:15:15 2003

Definately.

You most emphatically do NOT want copper going across your parking lot.
Besides the danger from lightning strikes and other electrostatic discharges
you run the risk of ground potentials differing significantly.  You could
wind up with a significant amount of current flowing across the coax just to
balance building grounds.  (This is why telcos insist on a single ground
point and have that point connected to an array of ground rods driven deep
in the ground.)

Tim

-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of
Robert E. Seastrom
Sent: Thursday, April 17, 2003 11:51
To: Mike (meuon) Harrison
Cc: [email protected]
Subject: Re: DS3 Coax..




"Mike (meuon) Harrison" <[email protected]> writes:

> I need to run a DS3 across our parking lot.. Seriously.
>
> What's the max length I can use coax for (I know, gotta use a GID),
> and what's the best brand/type of coax I can use? It'll be through
> innerduct.. Looking for some real world answers from people that do
> a LOT more of this than me..  (It might take 350-400 feet).

The textbook limit is 450' for 735 cable.  I've had poor luck pushing
the limit, and don't know offhand if using some other flavor of 75 ohm
cable buys you anything.

Were I in your position, I'd have glass pulled and use a coax to fiber
media converter such as http://www6.adc.com/ecom/hier?NODE=OND68947,
http://www.versitron.com/DS3T3.html, or
http://www.rad-direct.com/DATASHEET/FOM-T3.pdf (the latter of which
I've used personally) on each end.  No, it's not the cheap way to do
it, but it eliminates ground loops and other such nastiness that can
ruin your whole day.

                                        ---Rob